To make it feel super cosy , i would paint all three walls and have the big wall as a feature wall

Would be great to see it once it's done, best of luck

Thanks I'll post it

If you're having the television against the wall that is currently blue, I would paint the other three a warm mid toned grey to bridge the dark blue/pale ceiling. At the moment it looks very high contrast, and I feel that some walls in a warm grey would tie it all together.

Hi colour happy. Yes I don't really like the cream on the walls but it's on the ceiling and on the ceiling (that can be seen through the glass in the next room) so I had to have it in the high wall so I could do the edges using a roller and not scaffolding. Or I would do exactly what you suggest. But I hoped if I have my back to it (sitting on sofa) I won't notice it if I'm surrounded by blue? Yes the tv is going in the blue wall already painted. What do you think? I keep going in to start painting but bottling it!!

I don't dislike the cream, I just wondered if a warm grey would soften the effect. I think natural materials (often seen on barn conversions) are really set off with neutral colours but I do also like the blue. Is it a problem if you can see a bit of the other colour on the tall wall, and if you do, would it look better blue or a warm grey? What is on the floor?

I would paint all walls ( and the door/architrave) in the blue. Use masking tape to get a sharp line between the ceiling and walls. I would also paint the great tall pitch wall to match, and hang some big art on it, above and below the wall-light. Sexy, but not too dark ( as a snug) and anyway, you have quite some borrowed light from above.

Thanks for the comments I just daren't get a scaffold to get high enough to cut in the large wall! But I love your ideas. Any more advice very welcome for furnishings. I'm thinking of a corner sofa in mid grey fabric just for a change as all my other sofas are grey leather. But I do like velvet but bit cautious about splashing out on a velvet sofa do wondered if a chair or too could look nice?

Oops brown leather I meant.

I did the three walls ( I can reach without scaffolding) and it looks great so thanks for your encouragement and advice. I'll put another photo on when it's done as I'm sure I'll need some help with the decor. Thanks everyone x